Aufklaerung der fuer den Pflanzenschutzmitteleintrag ins Grundwasser verantwortlichen Vorgaenge, insbesondere im Hinblick auf die Trinkwasserversorgung Abschlussbericht

In this joint project, consisting of 10 separate projects, the behaviour of 21 pesticides, including Chlortoluron, Isoproturon, Parathion-ethyl, Pendimethalin and Terbuthylazin, has been investigated. The studies were carried out at 11 field sites which represent typical soils and farming situations. The pesticide transport has been observed all through the unsaturated zone down to the groundwater. Special investigations dealth with model studies in laboratory and field lysimeter scales. The results have been combined in computer models. A special study based on laboratory experiments and literature data dealt with the hygienic and toxicological evaluation of drinking water contamination by pesticides. Soil properties as humus content, grain size, and thickness of the unsaturated zone, as well as the pesticide properties solubility, sorption behaviour, and persistence influence the movement of pesticides into the groundwater. The processes decay and sorption are less effective below the humus rich and biologically active soil. Substances, which were metabolized and retarded in the upper soil, are moving in the deeper parts of the aquifer with practically the same velocity as water. The predictive exactness of decay- and transport models is strongly weakened by inhomogeneity and anisotropy of the subsoil properties. The evaluation of the total situation elucidates the lack of knowledge on the behaviour of the metabolites in subsurface water. Further scientific research is needed with respect to ground water contamination by these secondary compunds. (orig.)Available from TIB Hannover: F95B914+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEBundesministerium fuer Forschung und Technologie (BMFT), Bonn (Germany)DEGerman